Robotic transport system for an inventory storage module

ABSTRACT

In one embodiment, a trolley for an inventory storage module has a trolley frame and first and second track engagement features on opposed sides of the trolley frame that engage first and second rails of a track, respectively, such that the trolley frame is translatable along the track. The trolley has a power collector that is supported by the trolley frame, and that electrically couples to an electrical rail that is disposed above the trolley frame so as to collect power from the electrical rail as the trolley frame is translated along the track. The trolley has a robotic manipulator having a robotic arm and an end effector. The robotic arm extends below the trolley frame with respect to the vertical direction, and the end effector removeably couples inventory items to the robotic arm.

BACKGROUND

Inventory storage facilities such as warehouses and distribution centerscommonly employ shelving units to hold inventory items until they areneeded to fulfill a customer order. The shelving units are arranged inrows that are spaced from one another so as to define aisles between therows of shelving units. To store an inventory item on a desired shelvingunit, a human can carry the inventory item down an aisle in thewarehouse to the desired shelving unit and place the inventory item onthe desired shelving unit where it is stored until it is needed. When anorder is placed, a human can travel down the aisle to the desiredshelving unit, retrieve the inventory item from the desired shelvingunit, and place the inventory item on a conveyor belt that carries theinventory item downstream for packaging and shipping.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description will be better understood when readin conjunction with the appended drawings, in which there is shown inthe drawings example embodiments for the purposes of illustration. Itshould be understood, however, that the present disclosure is notlimited to the precise arrangements and instrumentalities shown. In thedrawings:

FIG. 1 shows a top perspective view of an inventory storage systemaccording to one embodiment having a plurality of storage modulesstacked on top of one another, each storage module having a pair ofshelving systems, a conveyor, and a robotic transport system having arobotic manipulator, where a portion of each shelving system is hiddento show the conveyors and robotic transport systems;

FIG. 2 shows a bottom perspective view of the storage system of FIG. 1,where a portion of each shelving system is hidden to show the conveyorsand robotic transport systems;

FIG. 3 shows an end view of a system having a plurality of verticalstacks of the storage modules of FIG. 1;

FIG. 4 shows a perspective enlarged view of a portion of the storagesystem of FIG. 1 with the conveyor belt of the lower conveyor removed;

FIG. 5 shows a top perspective view of a trolley and a portion of arobotic manipulator of a storage module of FIG. 1 according to oneembodiment;

FIG. 6 shows a bottom perspective view of the trolley of FIG. 6according to one embodiment;

FIG. 7 shows an enlarged end view of a conveyor and robotic transportsystem of the storage system of FIG. 1 according to one embodiment;

FIG. 8 shows an enlarged perspective view of an end of one of theconveyors of FIG. 1 according to one embodiment; and

FIG. 9 shows a simplified flow diagram of a method of operating thestorage system of FIG. 1 according to one embodiment.

DETAILED DESCRIPTION

In inventory storage facilities, storage density is an importantcharacteristic. Packing inventory items closer together reduces theoverall volume that is needed to store the inventory items. Thus, asmaller building or structure can be used to store inventory items thatare packed closer together. Further, in an existing storage facility,increasing density can free up warehouse space that can be used to storeadditional inventory items, thereby increasing the capacity of thestorage facility. Presented herein are inventory storage modules, andstorage systems that can have a higher storage density than theconventional shelving units discussed above.

Referring to FIGS. 1 and 2, an inventory storage system 10 according toone embodiment is shown that is configured to store inventory items. Ingeneral, the storage system 10 has at least one storage module 100. InFIGS. 1 and 2, three storage modules 100 are shown stacked on top of oneanother along a vertical direction V. Thus, it can be said that thestorage system 10 has at least one vertical stack of storage modules100. However, in alternative examples, the storage system 10 can have asfew as one storage module 100 or more than one storage module 100. Itwill be understood from the following description that the height,width, and length of the system 10 can be scalable to fit within adesired volume in a warehouse space by stacking storage modules 100 ontop of one another and next to one another.

The storage system 10 has a first end 102 and a second end 104 that arespaced from one another along a longitudinal direction L. Each storagemodule 100 extends between the first and second ends 102 and 104. Eachstorage module 100 comprises at least one shelving system 106 thatextends between the first and second ends 102 and 104 along thelongitudinal direction L. The storage system 10 defines at least oneaisle 105 disposed alongside of the at least one shelving system 106with respect to a lateral direction that is perpendicular to thelongitudinal direction L. Each storage module 100 can be configured tomove inventory items onto or remove inventory items from its at leastone shelving system 106. In one example as shown, each storage module100 can comprise a pair of shelving systems 106 that are spaced from oneanother along a lateral direction A that is perpendicular to thelongitudinal direction L and the vertical direction V. In suchembodiments, the aisle 105 can extend between the pair of shelvingsystems 106. However, in alternative embodiments, each storage module100 can have as few as one shelving system 106.

Each shelving system 106 has a first side 108 and a second side 110 thatare spaced from one another along the lateral direction A. Each shelvingsystem 106 has at least one shelf 112, such as a plurality of shelves112 that are spaced from one another along the vertical direction V. Theat least one shelf 112 defines a plurality of inventory storagelocations. Each storage location can be sized and configured to store aninventory item or a storage container 150. For example, each shelf 112can define a plurality of storage locations that are offset from oneanother along the longitudinal direction L. Each shelving system 106 canhave a length that is up to or equal to a length of the storage system10 from the first end 102 to the second end 104. However, in FIGS. 1 and2, only a portion of each shelving system 106 is shown for illustrativepurposes so that components between the shelving systems 106 can beviewed. In some embodiments, each shelf 112 can be angled downwards asit extends along the lateral direction A towards the aisle 105 such thatgravity draws inventory items or storage containers 150 stored on theshelf 112 towards the aisle 105.

Each storage module 100 has at least one conveyor 114 that is positionedalongside one of the first and second sides 108 and 110 of each of itsshelving systems 106. For example, each conveyor 114 can be positionedalong at least one of the first side 108 of one of its shelving systems106 and the second side 110 of the other one of its shelving systems106. Thus, each conveyor 114 can be disposed between a pair of shelvingsystems 106, such as in the aisle 105. As shown, the storage system 10can have a plurality of conveyors 114 that are spaced from one anotheralong the vertical direction V. It will be understood that, in variousembodiments, the storage system 10 can have as few as one conveyor 114or any suitable number of conveyors 114, including more than the threeconveyors 114 shown.

Each conveyor 114 extends between the first end 102 and the second end104 such that the conveyor 114 is elongate along the longitudinaldirection L. Each conveyor 114 is configured to convey inventory itemsalong the longitudinal direction L between the first end 102 and thesecond end 104. Each inventory item can be stored in a storage container150 that can be carried by the conveyor 114 or can be placed directly onthe conveyor 114. In either case, it can be said that the conveyor 114conveys the inventory item. In some embodiments, each conveyor 114 canbe configured to convey inventory items in a unidirectional manner suchthat the inventory items can be moved in only a first direction from oneof the first and second ends 102 and 104 to the other of the first andsecond ends 102 and 104. In such embodiments, one of the first andsecond ends 102 and 104 can be considered to be an incoming end, and theother one of the first and second ends 102 and 104 can be considered tobe an outgoing end. Alternatively, each conveyor 114 can operate in abidirectional manner such the inventory items can be selectivelyconveyed in one of the first direction and a second direction, oppositethe first direction.

Although not shown, the storage system 10 can include the storage module100 and at least one conveyor system (not shown) configured to conveyinventory items from processing that is upstream of the each storagemodule 100 to the first end 102 or from the first end 102 to processingthat is downstream of the each storage module 100. Similarly, thestorage system 10 can have at least one conveyor system (not shown)configured to convey inventory items from processing that is upstream ofeach storage module 100 to the second end 104 or from the second end 104to processing that is downstream of each storage module 100.

Each storage module 100 has a robotic transport system 116 that ispositioned alongside one of the first and second sides 108 and 110 ofeach shelving system 106 with respect to the lateral direction A. Forexample, each robotic transport system 116 can be positioned along atleast one of the first side 108 of one of the shelving systems 106 andthe second side 110 of the other one of the shelving systems 106. Thus,each robotic transport system 116 can be disposed between a pair ofshelving systems 106, such as along the aisle 105. As shown, the storagesystem 10 can have a plurality of robotic transport systems 116 that arespaced from one another along the vertical direction V. It will beunderstood that, in various embodiments, the storage system 10 can haveas few as one robotic transport system 116 or any suitable number ofrobotic transport systems 116, including more than the three robotictransport systems 116 shown.

The robotic transport system 116 of each storage module 100 is spacedabove the conveyor 114 of the storage module 100 along the verticaldirection V so as to service the conveyor 114. Each robotic transportsystem 116 has a track comprising at least one rail 118 that extendsbetween the first and second ends 102 and 104 along the longitudinaldirection L, and a trolley 120 (see e.g., FIGS. 5 and 6) configured totranslate along the track along the longitudinal direction L. Eachtrolley 120 has a robotic manipulator 122 with a robotic arm. Eachtrolley 120 is configured to move a respective robotic manipulator 122along the track to a position that is adjacent a select one of theinventory storage locations. Each robotic manipulator 122 is configuredto move an inventory item from at least one of (1) a respective one ofthe conveyors to the select one of the inventory storage locations and(2) the select one of the inventory storage locations to the respectiveone of the conveyors when the robotic manipulator 122 is disposedadjacent the select one of the inventory storage locations.

The operation of each storage module 100, and in particular, of therobotic transport system 116 and conveyor 114 of each storage module100, can be controlled by a controller 160 that is external to thestorage module 100. The controller 160 can communicate with a controllerthat is local to each storage module 100 wirelessly or via a wire. Insome examples, each storage module 100 can be controlled independentlyof the other storage modules 100. For example, each storage module 100can be configured to service its at least one shelving system 106independently of the other storage modules 100 servicing theirrespective shelving systems 106.

Turning briefly to FIG. 3, an inventory storage system 10 can include aplurality of the inventory storage modules 100 of FIGS. 1 and 2 that arepositioned side-by-side along the lateral direction A. In FIG. 3, twovertical stacks of storage modules 100 are shown; however, it will beunderstood that inventory storage systems of the disclosure can includemore than two vertical stacks of storage modules 100. Further, inventorysystem of the disclosure can include inventory storage modules 100positioned side-by-side without being arranged in vertical stacks. Asshown, each adjacent pair of the inventory storage modules 100 can shareone of the shelving systems 106. For example, a first one of the storagemodules 100(1) can include first and second shelving systems 106(1) and106(2), and a second one of the storage modules 100(2) can include thesecond shelving system 106(2) and a third shelving system 106(3). Thus,one of the shelving systems, such as the second shelving system 106(2),can be shared by the pair of first and second storage modules 100(1) and100(2). The second shelving system 106(2) can be positioned between theaisle 105 of the first storage module 100(1) and the aisle 105 of thesecond storage module 105. Thus, each robotic transport system 116 andconveyor 114 of the first storage module 100(1) can be configured toservice the second side 110 of the second shelving system 106(2), andeach robotic transport system 116 and conveyor 114 of the second storagemodule 100(2) can be configured to service the first side 108 of thesecond shelving system 106(2). Each storage module 100(1) and 100(2) canbe configured to operate independently of each other storage module100(1) and 100(2).

The storage system 10 can be configured to transfer storage containers150 or inventory items between aisles 105 along the lateral direction Athrough the shelves 112. For example, a robotic manipulator 122 in afirst aisle 105 can be configured to push storage containers 150 orinventory items from one side 108 or 110 of a shelf 112 to the otherside 108 or 110 of the shelf 112. The storage containers 150 orinventory items can then be accessed by a robotic manipulator 122 of anadjacent aisle 105. To support such embodiments, each shelf 112 that isbetween the two aisles 105 can be angled downwards towards the firstside 108 and angled downwards towards the second side 110, such that theshelf has a peak (not shown) between the first and second sides 108 and110. In this manner, storage containers 150 or inventory items can begravity fed from the peak towards the first and second sides 108 and110.

In an alternative embodiment, one or more aisles 105 of the system 10can be conveying aisles that include robotic transport system 116 andconveyors 114, and one or more aisles 105 can be transfer aisles thatinclude robotic transport system 116 but are devoid of conveyors 114.Thus, conveying aisles 105 can be configured to convey inventory itemsalong the conveyors 114 between the first and second ends 102 and 104.The transfer aisles 105 can be configured to pass storage containers 150or inventory items between conveying aisles 105 without conveyinginventory items along the conveyors 114 between the first and secondends 102 and 104.

Although not shown, one or more of the shelving systems 106 can includeas few as a single shelf 112. The shelf 112 can be configured to supporta pallet of inventory items that are not stored in storage containers150, and the robotic manipulator 122 can be configured to pull theinventory items directly off of the shelf 112. In some embodiments, oneor more of the shelving systems 106 can be configured to support atleast one pallet, and one or more other shelving systems 106 can beconfigured to support storage containers 150. Thus, the system 10 can beconfigurable to accommodate differently sized and shaped inventoryitems.

Although not shown, the inventory storage system 10 can have theplurality of storage modules 100 and at least one conveyor system (notshown) configured to convey inventory items from processing that isupstream of the storage modules 100 to the first end 102 or from thefirst end 102 to processing that is downstream of the storage modules100. Similarly, the storage system 10 can have at least one conveyorsystem (not shown) configured to convey inventory items from processingthat is upstream of the storage modules 100 to the second end 104 orfrom the second end 104 to processing that is downstream of the storagemodules 100.

Referring now more specifically to the enlarged views of FIGS. 4 and 8,each conveyor 114 is configured to convey inventory items between thefirst and second ends 102 and 104 of the storage module 100 along thelongitudinal direction L. In FIG. 4, the belt of the bottom conveyor 114is removed so that components below the belt can be viewed. Eachconveyor 114 has first and second sides 114 a and 114 b that are spacedfrom one another along the lateral direction A. Each conveyor 114 has anupper end 114 c and a lower end 114 d that are spaced from one anotheralong the vertical direction V. Each conveyor 114 has a conveyingsurface 114 e that is configured to carry inventory items along thelongitudinal direction L. Each conveying surface 114 e can extendbetween the first and second ends 102 and 104 of the storage module 100and between the first and second sides 114 a and 114 b of the conveyor114. Each conveying surface 114 e can be elongate along the longitudinaldirection L. Thus, each conveying surface 114 e can have a length alongthe longitudinal direction L that is greater than a width of theconveyor surface 114 e along the lateral direction A.

In general, each conveyor 114 can be implemented using any suitable typeof conveyor technology or any combination of suitable technologies. Forexample, each conveyor segment of the present disclosure can include atleast one moving surface, at least one rotating conveyor element, or anycombination thereof, where each moving surface or rotating conveyorelement at least partially defines the conveyor surface of the conveyorsegment. The at least one rotating conveyor element can include at leastone powered rotating conveyor element that is configured to rotate in adirection that drives the inventory items to translate along arespective one of the conveyor surfaces. Additionally or alternatively,the at least one rotating conveyor element can include at least oneunpowered rotating conveyor element that is configured to rotate inresponse to an item being translated thereon. Thus, each conveyor 114can include conveyor elements such as (without limitation) tracks,belts, rollers, skate wheels, balls, any other suitable conveyorelements for translating the inventory items, or any suitablecombination of conveyor elements.

In some examples as shown, each conveying surface 114 e can beconfigured as a conveyor belt. Further, in some examples, the conveyorbelt can include one or more dividers 114 f that are configured tomaintain a separation between adjacent inventory items, althoughembodiments are not limited to having dividers 114 f The dividers 114 fcan be spaced from one another along the longitudinal direction L, andcan each extend along the lateral direction A.

In some examples as shown, each conveyor 114 can include at least onepowered rotating conveyor element 114 g that is configured to rotate ina direction that drives the inventory items to move along thelongitudinal direction L. The at least one powered rotating conveyorelement 114 g can include powered rotating conveyor elements 114 gpositioned adjacent an end of the conveyor 114 so that they can beeasily accessed for repair or replacement. Additionally oralternatively, the at least one powered rotating conveyor element 114 gcan include powered rotating conveyor elements 114 g positioned betweenthe ends of the conveyor 114.

In some examples, the powered rotating conveyor elements 114 g can beconfigured to drive the conveyor surface 114 f to move. For example, thepowered rotating conveyor segments 114 g can be configured to drive theconveyor surface 114 to rotate along at least one of a first direction(e.g., clockwise) and a second direction (e.g., counter clockwise). Inother examples, the conveyors 114 can be devoid of a belt, and thepowered rotating conveyor elements 114 g can define the conveyorsurfaces 114 f. Each powered rotating conveyor element 114 g can include(without limitation) (i) a motor-driven roller that is driven by a motorthat is disposed within the roller such as those made by Interroll, (ii)a chain- or belt-driven roller that is driven by a chain or belt that isin turn driven by a motor that is external to the roller, (iii) anyother suitable powered rotating conveyor element, or (iv) anycombination thereof.

Additionally or alternatively, each conveyor 114 can include at leastone unpowered rotating conveyor element 114 h that rotates in responseto an item being translated thereon. Each unpowered rotating conveyorelement 114 g can include a roller as shown or can include a ball, askate wheel, any other suitable rotating conveyor element that isconfigured to roll in response to an object such as the conveyor belt orinventory item being translated thereon, or any combination of suchelements. The at least one unpowered rotating conveyor element 114 h caninclude a plurality of unpowered rotating conveyor elements that arepositioned between the ends of the conveyor 114, such as between a pairof the powered rotating conveyor elements 114 g.

As described above, each conveyor 114 can be configured to convey theinventory items in storage containers 150. Each storage container 150can be any suitable storage container configured to carry one or moreinventory items therein. Preferably, the inventory storage containers150 are open-top plastic totes configured to carry items in ane-commerce supply chain. The totes are of a size that an individualperson or robot can lift. For example, and with continued reference toFIG. 4, each storage container 150 can be a rectangular structure, suchas a bin or tote, formed from a rigid material such as high-densityplastic, wood, aluminum, or other suitable material. Each storagecontainer 150 can have a pair of opposed container sidewalls 150 a and150 b that are spaced opposite from one another along one of thelongitudinal and lateral directions. Each storage container 150 can havea pair of opposed container end walls 150 c and 150 d that are spacedopposite from one another along another one of the longitudinal andlateral directions. The opposed container end walls 150 c and 150 d canextend between the opposed container sidewalls 150 a and 150 b.Similarly, the opposed container sidewalls 150 a and 150 b can extendbetween the opposed container end walls 150 c and 150 d.

Each container 150 has a width Ws from one of the sidewalls 150 a and150 b to the other one of the sidewalls 150 a and 150 b, and can have alength Ls from one of the end walls 150 c and 150 d to the other one ofthe end walls 150 c and 150 d. In some embodiments, the length Ls can begreater than the width Ws. Each storage container 150 can further havean upper end 150 e and a bottom surface 150 f spaced from one anotheralong the vertical direction V. The bottom surface 150 f can extendbetween the opposed sidewalls 150 a and 150 b and between the opposedend walls 150 c and 150 d. The upper end 150 e can be open for ease ofaccess in placing inventory items into, and retrieving inventory itemsfrom, the storage container 150. Each container 150 can have a height Hsfrom the upper end 150 e to the bottom surface 150 f.

The size of a storage container 150 may be selected to optimize storagedensity of the storage module 100 or other suitable parameter. This maydepend on the size and type of items to be stored in the storagecontainer 150. For example, the storage container 150 may have a heightof about 18″, a width of about 18″, and a length of about 24″. However,the dimensions of the storage container 150 can be different than thosejust recited. The items held by the storage container 150 can be anysuitable item stored in a material storage facility including, forexample, personal electronic devices, computers, recreational equipment,food products, television sets, clothing, household supplies, automotiveparts, books, loaded pallets, and any other suitable object capable ofbeing stored.

The storage containers 150 can be stackable on top of one another. Forexample, the bottom surface 150 f of an upper one of the storagecontainers 150 can be received in the opening of the upper end 150 e ofa lower one of the storage containers 150. The upper end 150 e of thelower storage container 150 can be configured to support the bottomsurface 150 f of the upper storage container 150 such that the bottomsurface 150 f of the upper storage container 150 nests inside theopening of the lower storage container 150. Each container 150 can alsoinclude at least one protrusion 150 g, each extending outwardly from atleast one of the container sidewalls and end walls. For example, eachcontainer 150 can include a plurality of protrusions 150 g, eachextending outwardly from at least one of the sidewalls and end walls ata corner of the container 150 adjacent the upper end 150 e. At least oneprotrusion 150 g can define a handle that is configured to be configuredto be engaged by a human hand for carrying. At least one protrusion 150g can include a lower surface that is configured to be engaged by a tineof an end effector of a robotic manipulator 122, fork lift, or otherlifting machine. For example, a storage container 150 can include a pairof the protrusions 150 g disposed on opposite sides or ends of thecontainer 150 that are configured to engage a pair of tines.

Each storage container 150 may include an identifier (e.g., bar code, QRcode, radio-frequency identification (RFID) tag, and any other suitableidentifier). The identifier may be used to uniquely identify the storagecontainer 150. In some examples, the identifier may include non-volatiledata storage, which may be associated with the storage container 150and/or its contents. Data can be read/written to the data storage eachtime the stackable storage module is accessed. This data may containstatus of the stackable storage module, inventory stowed in thestackable storage module, and/or destination information for eachstorage container 150. In this manner, inventory information may beupdated when the identifiers are read.

With reference to FIGS. 7 and 8, each storage module 100 can include atleast one electrical rail 138 for each robotic transport system 116.Each electrical rail 138 can be configured to carry an electricalcurrent. For example, each storage module 100 can include a plurality ofelectrical rails 138 for each robotic transport system 116. In FIGS. 7and 8, four electrical rails 138 are shown, three of which can beconfigured to communicate power and one of which can be configured as aground. It will be understood that the electrical rails 138 can bealternatively configured. For example, each storage module 100 caninclude fewer than or more than four electrical rails 138 for eachrobotic transport system 116. Additionally or alternatively, fewer thanor more than three of the rails 138 can be configured to communicatepower. Additionally or alternatively, one or more of the electricalrails 138 can be configured to transmit and/or receive datacommunications.

Each electrical rail 138 can extend between the first and second ends102 and 104 of the storage module 100 along the longitudinal directionL. Each electrical rail 138 can be elongate along the longitudinaldirection L. Each electrical rail 138 is configured to electricallycouple to a power collector 136 of one of the trolleys 120. For example,each electrical rail 138 can define a recess 138 c that extends thereinso as to receive a projection 136 a of a power collector 136 (shown inFIG. 7 and discussed below). In particular, each electrical rail 138 canhave a first end 138 a and a second end 138 b that are spaced from oneanother along the vertical direction V. The first end 138 a can beattached to a respective conveyor 114, such as to the lower end 114 d ofthe respective conveyor 114. The second end 138 b can define the recess138 c that is configured to receive the projection 136 a of the powercollector 136. Thus, the recess 138 c can extend into the first end 138a along the vertical direction V. In alternative embodiments, eachelectrical rail 138 can be implemented in another suitable manner fortransferring power to the trolley 120. For example, each rail 138 can beimplemented with a lower surface instead of a recess 138 c, and thepower collector 136 of the trolley 120 can be configured to pressagainst the lower surface. Thus, each rail 138 can be configured tomechanically couple to a respective one of the power collectors 136through physical contact. However, as described below, each powercollector 136 could alternatively receive power via inductive couplingwithout physical contact between the power collector 136 and rail 138.

As shown in FIGS. 1 and 7, at least some of the storage modules 100 canbe stacked on top of one another so as to define a gap 140 between theconveyor 114 of an upper one of the storage modules 100 and the trolley120 of a lower one of the storage modules that is immediately below theupper one of the storage modules 100 with respect to the verticaldirection V. Each electrical rail 138 of the lower one of the storagemodules 100 can extend into the gap 140. In some examples, the storagemodules 100 can be stacked such that the upper storage module 100supports the rails 118 of the lower storage module 100. In particular,each rail 138 of the lower storage module 100 can be supported by thelower end 114 d of the conveyor 114 of the upper storage module 100. Forexample, each electrical rail 138 can extend from the lower end 114 dinto the gap 140. Note, however, that other electrical rails 138, suchas the electrical rails 138 corresponding to the upper-most storagemodule 100 in FIG. 1 (which is not below a conveyor 114), might not besupported by one of the conveyors 114.

Turning now to FIGS. 1, 2, and 4, as described above, each robotictransport system 116 can include a trolley 120 and a track having atleast one rail 118. Each rail 118 can be elongate along the longitudinaldirection L. In some examples, the track of each robotic transportsystem 116 can include a pair of rails 118 that are spaced apart fromone another along the lateral direction A. Alternatively, each robotictransport system 116 can include just a single rail (i.e., a monorail).As shown in FIG. 7, each rail 118 can have an L-shape in a plane that isperpendicular to the longitudinal direction L. Each rail 118 can includeat least one guide surface that is configured to support a rollingelement such as a wheel or bearing of the trolley 120. For example, asshown in FIG. 7, each rail 118 can have a horizontal guide surface 118 athat extends along the longitudinal and lateral directions. Each rail118 can optionally have a vertical guide surface 118 b that extendsalong the longitudinal and vertical directions. Each rail 118 canoptionally have a surface 118 c opposite the horizontal guide surface118 a. In alternative examples, each rail 118 can have another suitableshape such as (without limitation) a C-shape, a U-shape, or a T-shape.Further, in alternative examples, each rail 118 can be configured as atrack having a bearing such as a linear bearing or a track having achain.

Referring now more specifically to FIGS. 5 to 7, each trolley 120 has atrolley frame 124. The trolley frame 124 has first and second frame ends124 a and 124 b that are spaced from one another along the longitudinaldirection L. The trolley frame 124 has first and second frame sides 124c and 124 d that are spaced from one another along the lateral directionA. The trolley frame 124 has upper and lower frame ends 124 e and 124 fthat are spaced from one another along the vertical direction V. In oneexample as shown in FIGS. 6 and 7, each trolley 120 can have an upperwall 124 g that defines the upper frame end 124 e. The upper wall 124 gcan have an outer surface and an inner surface that are spaced from oneanother along the vertical direction V.

Each trolley 120 has at least one track engagement feature 126 that isconfigured to engage the track so that the trolley frame 124 cantranslate along the track along the longitudinal direction L. Each ofthe at least one track engagement feature 126 can be disposed at one ofthe frame sides 124 c or 124 d or can be disposed at another location ofthe trolley frame 124. In some examples as shown in FIGS. 5-7, the atleast one track engagement feature 126 can include a pair of trackengagement features 126 that are spaced from one another along thelateral direction A. For example, the pair can include first and secondtrack engagement features 126 coupled to the trolley frame 124 at thefirst and second frame sides 124 c and 124 d, respectively. The firstand second track engagement features 126 can be configured to engage thefirst and second rails 118 of a track, respectively, such that thetrolley frame 124 is translatable along the track along the longitudinaldirection L. The at least one track engagement feature 126 canadditionally include a second pair of track engagement features 126 thatare spaced from one another along the lateral direction A and spacedfrom the pair along the longitudinal direction L. The second pair caninclude first and second track engagement features 126 coupled to thetrolley frame 124 at the first and second frame sides 124 c and 124 d,respectively. The first and second track engagement features 126 of thesecond pair can be configured to engage the first and second rails 118of a track, respectively.

Each track engagement feature 126 can include a wheel 128 as shown inFIGS. 5-7. Each wheel 128 can be configured to rotate around an axisthat extends along the lateral direction A. Further, each wheel 128 canbe configured to engage the horizontal guide surface 118 a of one of therails 118. However, it will be understood that each track engagementfeature 126 can be configured in another manner. For example, each trackengagement feature 126 can include an axle (not shown) that isconfigured to engage a wheel, bearing, or chain of the track. Thetrolley 120 can include at least one motor 132 supported by the trolleyframe 124. Each motor 132 can be configured to cause at least one of thewheels 128 to rotate so as to cause the trolley 120 to move along thetrack along the longitudinal direction. For example, each motor 132 candrive an axle of one of the wheels 128 to rotate. Each motor 132 canreceive power from at least one of the power collectors 136.

Each track engagement feature 126 can include a wheel 130 that isconfigured to rotate around an axis that extends along the verticaldirection V. Each wheel 130 can be configured to engage the verticalguide surface 118 b of one of the rails 118. The wheels 130 can maintainpositioning of the trolley frame 124 between the rails 118 with respectto the lateral direction L so as to limit skew of the trolley frame 124and reduce the likelihood of one or more of the wheels 128 becomingdisengaged from the rails 118.

Each track engagement feature 126 can additionally or alternativelyinclude a clamp 134 (see e.g., the enlarge view in FIG. 7) that isconfigured to lock a position of the trolley 120 on the track withrespect to movement along the longitudinal direction L. The clamp 134can also be configured to reduce the likelihood that the trolley 120tips or rolls over about an axis that extends along the longitudinaldirection L due to torque that is placed on the trolley 120 when therobotic arm extends beyond one of the first and second frame sides 124 cand 124 d with respect to the lateral direction A. The clamp 134 can bean powered toggle clamp such as (without limitation) a pneumatic toggleclamp manufactured by Destaco. The clamp 134 can receive power from theat least one power collector 136. The clamp 134 can include an actuator134 a and an arm 134 b that is coupled to the actuator 134 a. Theactuator 134 a can be configured to cause the arm 134 b to move betweena clamped position, wherein the arm 134 applies a pressure to one of therails 118 so as to lock the position of the trolley 120, and a releasedposition, wherein the pressure applied by the arm 134 to the rail 118 isat least partially removed so as to allow the trolley 120 to move alongthe rail 118.

The actuator 134 a can be configured to move the arm 134 b along thevertical direction V towards a respective one of the rails 118 such thatthe arm 134 b engages the rail 118 in the clamped position and clamps orsqueezes the rail between the arm 134 b and one of the wheels 128 asshown in FIG. 7. The actuator 134 a can also be configured to move thearm 134 b along the vertical direction V away from the respective one ofthe rails 118 such that the arm 134 b at least partially releasespressure on the rail 118 in the released position, thereby allowing therail 118 to pass between the arm 134 b and the wheel 128 as the trolley120 moves along the longitudinal direction L.

Referring to FIGS. 5 and 7, each trolley 120 can include at least onepower collector 136, each being configured to electrically couple to arespective one of the electrical rails 138. Thus, each power collector136 can be configured to receive an electrical current from a respectiveone of the electrical rails 138. For example, each trolley 120 caninclude a plurality of power collectors 136. In FIGS. 5 and 7, fourpower collectors 136 are shown, three of which can be configured toreceive power and one of which can be configured as a ground. The powercollectors can be configured to supply the power that it receives to atleast one, up to all, of (i) a controller 136, (ii) a motor 132, (iii) aclamp 134, (iv) a robotic arm 123, and (v) an end effector 125. It willbe understood that the power collectors 136 can be alternativelyconfigured. For example, each trolley 120 can include fewer than or morethan four power collectors 136. Additionally or alternatively, fewerthan or more than three of the power collectors 136 can be configured tocommunicate power. Additionally or alternatively, one or more of thepower collectors 136 can be configured to transmit and/or receive datacommunications.

Each power collector 136 can include at least one projection 136 a thatis configured to be received in a recess 138 c of one of the rails 138.Each projection 136 a can extend from the upper frame end 124 e of thetrolley frame 120, such as from the outer surface of the upper wall 124g of the trolley frame 124. Each projection 136 a can have a lengthalong the longitudinal direction L that is greater than a width of theprojection 136 a along the lateral direction A. Each projection 136 acan have a height along the vertical direction V that is less than thelength. Thus, each projection 136 a can be elongate along thelongitudinal direction L. It will be understood that the powercollectors 136 can be configured in any suitably alternative manner. Forexample, each projection 136 a can have another suitable shape such as aleaf spring that is configured to press against a surface of one of therails 138, rather than be received in the recess 138 c of one of therails 138. Thus, it can be said that each power collector 136 isconfigured to mechanically couple to a respective one of the rails 138.However, in alternative embodiments, each power collector canelectrically couple to one of the rails 138 or other power sourcewithout mechanically coupling to the rail. For example, each powercollector can inductively couple to a power source that is stationaryrelative to the trolley. In such a case, each power collector and eachpower source can include an inductive coil.

With continued reference to FIG. 7, the storage system 10 can include atleast one inventory transfer system 117 that includes a conveyor 114,and a robotic transport system 116 disposed below the conveyor 114 alongthe vertical direction V. The conveyor 114 can be a conveyor of an upperone of the storage modules 100, and the robotic transport system 116 canbe the robotic transport system of a lower one of the storage modules100 immediately below the upper storage module 100. Each inventorytransfer system 117 can define a gap 140 between the conveyor 114 andthe trolley 120 of the robotic transport system 116. For example, thegap can be defined between the upper frame end 124 e of the trolley 120and the lower end 114 d of the conveyor 114, such as between the outersurface of the upper wall 124 g of the upper frame end 124 e and thelower end 114 d of the conveyor 114. The gap 140 can have a height alongthe vertical direction V. The height can be inversely proportional to astorage density of the storage module 100. For example, a smaller heightcan enable a larger storage density than a larger height. Therefore,preferably, the height of the gap 140 is preferably relatively small. Inone example, the height can be substantially equal to a combined heightof one of the rails 138 and one of the power collectors 136 when theyare mated to one another. In another example, the height can be in arange from about ⅛″ to about 6″.

Referring now more specifically to FIG. 6, each trolley 120 can includea robotic manipulator 122 that is supported by the trolley frame 124.The robotic manipulator 122 can include a robotic arm 123 and an endeffector 125 (labeled in FIG. 4). The robotic manipulator 122 canreceive power from the at least one power collector 136. The robotic arm123 can have a first arm end 123 a and a second arm end 123 b that arespaced from one another. The first arm end 123 a can be attached to thetrolley frame 124 between the first and second frame sides 124 c and 124d and between the first and second frame ends 124 a and 124 b. Therobotic arm 123 can extend below the trolley frame 124 with respect tothe vertical direction V. The first arm end 123 a can be attached to thetrolley frame 124, such as to the inner surface of the upper wall 124 g.The track engagement features 126 can be outwardly spaced from the firstarm end 123 a with respect to the longitudinal direction L. For example,the first arm end 123 a can be attached to the trolley frame 124 between(i) a first pair of track engagement features 126 that are spaced fromone another along the lateral direction A, and (ii) a second pair oftrack engagement features 126 that are spaced from one another along thelateral direction A and spaced from the first pair of track engagementfeatures with respect to the longitudinal direction A.

The robotic arm 123 can have a plurality of joints (e.g., 123 c, 123 d,123 e, and 123 f) that are configured to allow the robotic arm 123 toarticulate. For example, the robotic arm 123 can have a joint 123 c thatis configured to rotate the robotic arm 123 relative to the trolleyframe 124 about an axis that extends along the vertical direction V. Thejoint 123 c can be positioned adjacent the first arm end 123 a.Additionally or alternatively, the robotic arm 123 can have at least oneelbow joint 123 d, 123 e, and 123 f that is configured to allowdifferent portions of the robotic arm 123 to rotate about a horizontalaxis relative to one another and/or to allow the end effector 125 torotate about a horizontal axis relative to the second arm end 123 b. Itwill be understood that the robotic arm could be configured in anysuitable alternative manner.

The end effector 125 can be coupled to the second arm end 123 b. The endeffector 125 is configured to removeably couple an inventory item to therobotic arm 123. In one example, the end effector 125 can be a vacuumend effector that grasps objects using suction. In such embodiments, thetrolley 120 can include a vacuum generator 144 that is configured toproduce the suction at the end effector 125. The vacuum generator 144can receive power from the at least one power collector 136. The vacuumgenerator 144 can be attached to the trolley frame 124, such as to theinner surface of the upper wall 124 g. The vacuum generator 144 can beoutwardly spaced from the first arm end 123 a of the robotic manipulatorwith respect to the longitudinal direction L. The vacuum generator 144can receive power from the at least one power collector 136.

It will be understood that different end effectors may be employeddepending on the application for the robotic manipulator 122. Forexample, categories of end effectors that can be employed include(without limitation): soft robotic end effectors, electro-adhesion endeffectors, and mechanical or electromechanical end effectors. Softrobotic end effectors may generally include flexible structures that maybe manipulated between various orientations. The structures may includesilicon bodies or other flexible material. Manipulation of the flexiblematerial may be achieved through use of flexible actuators such as airmuscles (e.g., contractile or extensional devices operated bypressurized air movement relative to filling or emptying a pneumaticbladder), electro-active polymers (e.g., polymers which change size orshape when stimulated by an electric field), or ferrofluids (e.g.,fluids having suspended ferro-magnetic particles capable of altering asize or shape of the fluid volume when subjected to a magnetic field).Electro-adhesion end effectors can include an array of electrodesarranged along a flexible or rigid substrate capable of applying acharge (akin to static electricity) that can adhere an object to thesubstrate portions that are in contact with the object. Mechanical orelectromechanical end effectors may include pinchers, claws, grippers,or other rigid components that may be actuated relative to one anotherfor grasping an object. Other end effectors may also be utilized tofacilitate additional grasping functions.

Each robotic manipulator 122 can be configured to perform at least one,up to all, of (i) removing storage containers 150 from the shelvingsystems 106, (ii) retrieving inventory items from the storage containers150, (iii) stowing inventory items into the storage containers 150, and(iv) stowing the storage containers 150 onto the shelving systems 106.Each robotic manipulator 122 can be any suitable material handlingrobot. Each robotic manipulator 122 may include any suitable type andnumber of sensors disposed throughout the robotic manipulator (e.g.,sensors in the base, in the arm, in joints in the arm, in an endeffector, or in any other suitable location). The sensors can includesensors configured to detect pressure, force, weight, light, objects,slippage, and any other information that may be used to control and/ormonitor the operation of the robotic manipulator, and an end effector.

The sensors may be in communication with a controller 142 that is localto the trolley 120 and/or may be in direct communication with acontroller 160 (see FIG. 1) that is external to the trolley 120. In thismanner, the controller or controllers may control the operation of therobotic manipulator 122 and the end effector 125 based at least in parton sensing information received from the sensors. The sensors mayinclude any suitable combination of sensors capable of detecting depthof objects, capturing RGB and other images of objects, scanningmachine-readable information, capturing thermal images, detectingposition and orientation of objects, and performing any other suitablesensing as described herein.

With continued reference to FIG. 6, each trolley 120 can include acontroller 142 that is supported by the trolley frame 124. Thecontroller 142 can be attached to the trolley frame 124, such as to theinner surface of the upper wall 124 g. The controller 142 can bedisposed outwardly from the first arm end 123 a of robotic manipulator122 with respect to the longitudinal direction A. The controller 142 canreceive power from the at least one power collector 136. The controller142 may include any suitable control circuitry capable of receiving,processing, executing, and generating instructions relating to theoperation of at least one, up to all, of (i) the motor 132, (ii) theclamp 134, (iii) the robotic arm 123, and (iv) the end effector 125. Forexample, the controller 142 can be configured to control the roboticmanipulator 122 so as to move the end effector 125 to an inventory itemthat is disposed outwardly of one of the first and second frame sides124 c and 124 d with respect to the lateral direction A and to couplethe inventory item to the robotic arm 123. As another example, thecontroller 142 can be configured to driving the at least one motor 132to cause the trolley 120 to move along the track to a desired position.As yet another example, the controller 142 can be configured to move theclamp 134 between the clamped and released positions.

Referring back to FIG. 1, the aisle 105 occupies space that couldotherwise be used for storing inventory items. The width of the aisle105 along the lateral direction A is preferably designed to be as smallas possible, while being large enough for inventory items and storagecontainers 150 to be conveyed along the aisle. Therefore, the width ofthe aisle 105 along the lateral direction A is preferably close to thewidth of the storage containers 150 so as to limit the amount of aislespace that could otherwise be used for storage. The aisle width can bedependent upon a width of each trolley 120 along the lateral directionA. The width of each trolley 120 can be kept relatively small by spacingat least one, up to all, of the controller 142, the vacuum generator144, the at least one motor 132, the at least one power collector 136,and the at least one track engagement feature 126 outwardly from thefirst arm end 123 a of the robotic manipulator 122 with respect to thelongitudinal direction L. Thus, some, up to all, of the electricalcomponents of the trolley 120, except for the robotic manipulator 122,can be disposed outwardly of the robotic manipulator 122 with respect tothe longitudinal direction L. In contrast, spacing these componentsoutwardly from the first arm end 123 a along the lateral direction Awould increase the width of the trolley 120, and consequently, the widthof the aisle 105.

Turning now to FIGS. 1 and 9, a method 200 of retrieving an inventoryitem from a storage system such as the system 10 of FIG. 1 is shown. Instep 202, the method comprises causing a desired storage container 150to be identified from a plurality of storage containers 150 supported bythe inventory storage system 10, where each storage container 150 isconfigured to store at least one inventory item therein. In step 204,the method comprises causing a location of the desired storage container150 within a select storage module 100 of the inventory storage system10 to be identified by identifying a select shelf 112 of a shelvingsystem 106 of the select storage module 100 that supports the desiredstorage container 150 from a plurality of shelves 112 of the shelvingsystem 106 that are spaced from one another along the vertical directionV.

In step 206, the method comprises causing a trolley 120 of the selectstorage module 100 that supports a robotic manipulator 122 to move alonga track along the longitudinal direction L to a position that isadjacent the location of the desired storage container 150, where thetrack is positioned alongside the shelving system 106 with respect tothe lateral direction L. Step 206 can optionally include causing thelocation of the desired storage container 150 on the select shelf 112 tobe identified from a plurality of longitudinal storage positions on theselect shelf 112 that are offset from one another along the longitudinaldirection L. Further, in embodiments that employ a plurality of storagemodules 100, step 206 can include causing the select storage module 100that stores the desired storage container 150 to be identified from aplurality of storage modules 100 of the inventory storage system 10,where each storage module 100 includes at least one shelving system 106,a robotic transport system 116 having a track and a trolley 120 thatmoves along the track, and a robotic manipulator 122 supported by thetrolley 120. In particular, the select storage module 100 can beidentified from a plurality of storage modules 100 that are stacked ontop of one another along the vertical direction V and/or arrangedside-by-side along the lateral direction L.

In step 208, the method comprises causing the robotic manipulator 122 ofthe trolley 120 to remove the desired storage container 150 from theshelving system 106 and place the desired storage container 150 onto aconveyor 114 of the select storage module 100 that is disposed below thetrolley 120. Step 208 can include causing the robotic manipulator 122 tomove an end effector 125 of the robotic manipulator 122 to the desiredstorage container 150, and to removeably couple the robotic manipulator122 to the desired storage container 150. Step 208 can further includecausing the robotic manipulator 122 to move the desired storagecontainer 150 to the conveyor 114, and to decouple the roboticmanipulator 122 from the desired storage container 150.

In step 210, the method can include causing the robotic manipulator 122to remove an inventory item from the desired storage container 150 whenthe desired storage container 150 is positioned on the conveyor 114, andplace the inventory item onto the conveyor 114. In step 212, the methodcan comprise causing the robotic manipulator 122 to place the desiredstorage container 150 back onto the shelving system 106 after placingthe inventory item on the conveyor 114. Step 212 can include causing theend effector 125 to removeably couple the robotic manipulator 122 to thedesired storage container 150, and to move the desired storage container150 to the shelving system 106. In step 214, the method can comprisecausing the conveyor 114 to move the inventory item along thelongitudinal direction L to an end of the inventory storage module 100.Note that, in alternative embodiments or in some iterations of themethod, steps 210 and 212 can be omitted, and step 214 can comprisecausing the conveyor 114 to move the desired storage container 150 thatcarries the inventory item to move the storage container 150 along thelongitudinal direction L to an end of the inventory storage module 100.Further, in alternative embodiments or in some iterations of the method,the robotic manipulator 122 can grasp inventory items directly from theshelfing system 106 without grasping storage containers 150 carrying theinventory items, and then can place the inventory items onto theconveyor 114 without placing storage containers 150 on the conveyor 114.

It should be noted that the illustrations and descriptions of theembodiments shown in the figures are for exemplary purposes only, andshould not be construed limiting the disclosure. One skilled in the artwill appreciate that the present disclosure contemplates variousembodiments. Additionally, it should be understood that the conceptsdescribed above with the above-described embodiments may be employedalone or in combination with any of the other embodiments describedabove. It should further be appreciated that the various alternativeembodiments described above with respect to one illustrated embodimentcan apply to all embodiments as described herein, unless otherwiseindicated.

Unless explicitly stated otherwise, each numerical value and rangeshould be interpreted as being approximate as if the word “about” or“approximately” preceded the value or range.

It should be understood that the steps of exemplary methods set forthherein are not necessarily required to be performed in the orderdescribed, and the order of the steps of such methods should beunderstood to be merely exemplary. Likewise, additional steps may beincluded in such methods, and certain steps may be omitted or combined,in methods consistent with various embodiments.

Although the elements in the following method claims, if any, arerecited in a particular sequence with corresponding labeling, unless theclaim recitations otherwise imply a particular sequence for implementingsome or all of those elements, those elements are not necessarilyintended to be limited to being implemented in that particular sequence.

What is claimed:
 1. A system for an inventory storage module, the systemcomprising a trolley that comprises: a trolley frame having first andsecond frame ends that are spaced from one another along a longitudinaldirection, first and second frame sides that are spaced from one anotheralong a lateral direction, perpendicular to the longitudinal direction,and upper frame end and an underside that are spaced from one anotheralong a vertical direction, perpendicular to both the longitudinal andlateral directions, the upper frame end and the underside extendingbetween the first and second frame sides and between the first andsecond frame ends; first and second pairs of wheels that are spaced fromone another along the longitudinal direction, each pair including firstand second wheels coupled to the trolley frame at the first and secondframe sides, respectively, the first and second wheels of each pairconfigured to engage first and second rails of a track, respectively,such that the trolley frame is translatable along the track along thelongitudinal direction; a plurality of power collectors that aresupported by the trolley frame, each including a projection that extendsabove the upper frame end such that each power collector is configuredto electrically couple to a corresponding electrical rail that isdisposed above the trolley frame so as to collect power from theelectrical rail as the trolley frame is translated along the track; anda robotic manipulator having: a robotic arm having first and second armends that are spaced from one another, the first arm end being attachedto the trolley frame at the underside of the trolley frame at a locationthat is between the first and second frame sides and between the firstand second frame ends such that the robotic arm extends from theunderside of the trolley frame and beneath the underside of the trolleyframe with respect to the vertical direction; and a vacuum end effectorcoupled to the second arm end, the vacuum end effector configured toapply suction to an inventory item to removably couple the inventoryitem to the second arm end, wherein the robotic manipulator is poweredby the power collected from the plurality of power collectors and isconfigured to move the end effector to an inventory item that isdisposed outwardly of one of the first and second frame sides withrespect to the lateral direction and couple the inventory item to thesecond arm end.
 2. The system of claim 1, comprising the electricalrails, and a conveyor disposed above the trolley along the verticaldirection, wherein the system defines a gap between the conveyor and theupper frame end of the trolley frame, the gap having a height along thevertical direction that is substantially equal to a combined height ofthe at least one electrical rail and the at least one power collectorwhen they are mated to one another.
 3. The system of claim 1, whereinthe trolley comprises at least one clamp that is configured to movebetween a clamped position, wherein the clamp applies a pressure to atleast one of the first and second rails so as to fix a position of thetrolley with respect to movement along at least one of the vertical andlongitudinal directions, and a released position, wherein the pressureis at least partially released such that the trolley is permitted tomove along the track along the longitudinal direction.
 4. A trolley foran inventory storage module, the trolley comprising: a trolley framehaving first and second frame ends that are spaced from one anotheralong a longitudinal direction, first and second frame sides that arespaced from one another along a lateral direction, perpendicular to thelongitudinal direction, and upper frame end and an underside that arespaced from one another along a vertical direction, perpendicular toboth the longitudinal and lateral directions, the upper frame end andthe underside extending between the first and second frame sides andbetween the first and second frame ends; first and second trackengagement features coupled to the trolley frame at the first and secondframe sides, respectively, the first and second track engagementfeatures configured to engage first and second rails of a track,respectively, such that the trolley frame is translatable along thetrack along the longitudinal direction; at least one power collectorthat is supported by the trolley frame, each configured to electricallycouple to an electrical rail that is disposed above the trolley frame soas to collect power from the electrical rail as the trolley frame istranslated along the track; and a robotic manipulator having a roboticarm that has a first arm end that is attached to the trolley frame atthe underside of the trolley frame such that the first arm end extendsfrom the underside of the trolley frame and beneath the underside of thetrolley frame with respect to the vertical direction, and an endeffector coupled to robotic arm and configured to removably couple aninventory item to the robotic arm, wherein the robotic manipulator ispowered by the power collected from the at least one power collector andis configured to move the end effector to an inventory item that isdisposed outwardly of one of the first and second frame sides withrespect to the lateral direction and couple the inventory item to therobotic arm.
 5. The trolley of claim 4, wherein each of the first andsecond track engagement features includes a wheel configured to rotatearound an axis that extends along the lateral direction and to engage ahorizontal guide surface of a respective one of the first and secondrails.
 6. The trolley of claim 5, wherein the trolley includes at leastone motor supported by the trolley frame that is configured to cause atleast one of the wheels to rotate so as to cause the trolley to movealong the track along the longitudinal direction.
 7. The trolley ofclaim 4, wherein the first and second track engagement features eachinclude first and second wheels that are each configured to rotatearound an axis that extends along the vertical direction, the first andsecond wheels configured to engage vertical guide surfaces of the firstand second rails, respectively, so as to maintain positioning of thetrolley frame between the first and second rails.
 8. The trolley ofclaim 4, wherein each track engagement feature includes a clamp that isconfigured to move between a clamped position, wherein a position of thetrolley is fixed on the track with respect to movement along at leastone of the vertical and longitudinal directions, and a releasedposition, wherein the trolley is permitted to move along the track alongthe longitudinal direction.
 9. The trolley of claim 8, wherein the clampincludes an arm, and the clamp is configured to move the arm such thatthe arm applies pressure to the track, thereby squeezing the trackbetween the arm and a respective one of the engagement features when theclamp is in the clamped position.
 10. The trolley of claim 4, whereinthe at least one power collector includes at least two power collectorsconfigured to receive power and at least one power collector configuredto couple to ground.
 11. The trolley of claim 4, wherein the at leastone power collector is configured to supply the collected power that itreceives to at least one of (i) a controller that controls movement ofthe trolley, (ii) a motor that controls movement of at least one trackengagement features, (iii) the robotic arm, and (iv) the end effector ofthe trolley.
 12. The trolley of claim 4, wherein each power collectorincludes at least one projection that extends above the upper frame endof the trolley frame and that is configured to engage a respectiveelectrical rail.
 13. The trolley of claim 4, wherein the projection ofeach power collector is configured to be received in a recess of acorresponding one of the electrical rails.
 14. The trolley of claim 4,wherein the trolley includes a second pair of track engagement featuresthat are spaced from the first and second track engagement featuresalong the longitudinal direction, the second pair including first andsecond track engagement features that are coupled to the trolley frameat the first and second frame sides, respectively, and that areconfigured to engage the first and second rails of the track,respectively.
 15. The trolley of claim 14, wherein the first and secondpairs of track engagement features are disposed outwardly of a first armend of the robotic arm with respect to the longitudinal direction, thefirst arm end being attached to the trolley frame.
 16. The trolley ofclaim 4, comprising a controller supported by the trolley frame, thecontroller configured to control the robotic manipulator so as to movethe end effector to an inventory item that is disposed outwardly of oneof the first and second frame sides with respect to the lateraldirection and to couple the inventory item to the robotic arm.
 17. Thetrolley of claim 16, wherein the controller is disposed outwardly from afirst arm end of the robotic arm with respect to the longitudinaldirection, the first arm end being attached to the trolley frame. 18.The trolley of claim 4, wherein the end effector is configured as avacuum end effector that grasps objects using suction, and the trolleyincludes a vacuum generator that is supported by the trolley frame andis configured to apply suction to the end effector.
 19. A systemcomprising the trolley of claim 4, the system comprising the at leastone electrical rail, and a conveyor disposed above the trolley along thevertical direction, wherein the system defines a gap between theconveyor and the upper frame end of the trolley frame, the gap having aheight along the vertical direction that is substantially equal to acombined height of the at least one electrical rail and the at least onepower collector when they are mated to one another.
 20. A systemcomprising the trolley of claim 4, the system comprising a conveyordisposed spaced below the trolley along the vertical direction so as todefine a space between the conveyor and the trolley, wherein the roboticmanipulator is configured to place inventory items onto the conveyor.